Spark plug



L. COUGHLIN July 28, 1953 INVENTOR.

Patented July 28, 1953 UNITED STATES PATENT OFFICE SPARK PLUG Leo Goughlin, Toronto, Ontario, Canada Application June 9, 1950, Serial No. 167,064

1 Claim.

The invention relates to improvements in spark plugs as described in the present specification and shown in the accompanying drawings that form a part of the same. a

The invention concerns particularly that type of spark plug wherein means is provided for heating hydrocarbon vapors in the vicinity of the plugs.

Spark plugs equipped for this purpose, as heretofore known, wherein a heating wire has been conducted through the porcelain core have been impractical for various reasons, chief of which is the very high percentage of breakage of porcelains due to the excessive heat generated therein by the red hot heating wires.

The main objects of the present invention are to provide simple and efficient means for preheating the combustion chamber and thus gasify the fuel in preparation for ignition by the spark plugs, so as to insure easy starting; to provide for the feeding of electric current through the porcelain core to the point at which heat is desirable, without subjecting the interior of the core to sudden changes of temperature; and to keep the points of the plugs free of carbon and other foreign matter which would tend to decrease their efficiency.

With the above and other objects in view the invention consists in the novel features of construction, arrangements and combinations of parts set out in the present specification and more particularly pointed out in the claim for novelty following.

In describing the invention reference will be made to the accompanying drawings, in which:

Figure 1 is a side elevation mostly in vertical section, of a spark plug embodying my invention.

Figure 2 is a side elevation of the structure shown in Figure 1, with a portion of the shell broken away.

Figure 3 is a cross sectional view taken on the line 33 of Figure 1.

Figure 4 is a bottom plan view of Figure 2.

Figure 5 is a side elevation of the heating element.

Like numerals of reference indicate corresponding parts in the various figures.

Referring to the drawings, in which one complete embodiment of the invention is shown, I is the core which may be made of porcelain or other heat resistant material having the required insulating properties.

The core is adapted to carry the conventional electrode 2 projecting from its opposite ends, the projecting lower portion cooperating with the 2 ground wire 3 extending from the shell 4, andthe upwardly projecting end being adapted to accommodate the usual threaded terminal connection 5.

The core has an intermediate peripheral enlargement or flange 6 adapted to fit within an enlargement I of the upper portion of thebore of the shell, over the interior annular shoulder 8 formed by such enlargement, and to be locked by means of the plug Sthreading into the bore above the said flange 6, there being provided suitable sealing gaskets IE and l I.

The portion of the core from the lower end of the flange 6 tapers gradually downwardly, as shown at [2, and extends through a chamber l3 in the shell and terminates within the exteriorly threaded neck I4 of the shell, slightly short of the lower end of the electrode.

The core extends a considerable distance upwardly abov the plug 9 and for a portion of such distance is of even diameter and then is reduced abruptly, as at I5, and continues for a relatively short distance in a straight line and then tapers gradually to its top end at which is located the connector 5.

I1 is a heating element which is preferably coiled around that portion of the downwardly tapered part I2 of the core which lies within the chamber l3 of the shell, said heating element having its lower end offset and spot welded or otherwise secured to the inner wall of the shell, as at l8.

The heating element has connection at its inner end with the lower end of an electric conducting wire l9 which extends upwardly through a passage 20 formed lengthwise of the core parallel with and spaced from the electrode 2, and emerges from said passage onto the face of the straight wall portion !6 and terminates substantially even with the end of said straight wall portion.

2| is a metal band which is adapted to slide over the tapered top portion of the core and into engaging position over the portion of the conducting wire l9 which extends along the straight wall portion of the core. The band 2| constitutes a terminal contact for an electric conducting wire 22 leading from the car battery.

The Wire 22 preferably extends through, or is attached to, a plug 23 which threads into an opening in the band 2| into contact with the said wire l9 whereby to provide current to the heating coil I! when the current is turned on by means of a suitable switch (not shown).

When it is desired to start the motor the current is supplied to the conducting wires 23 and flows through the wires l9, without heating the cores, to the heating coils encircling the tapered portions of the cores located in the chambers I3 of the respective shells. The heat thus applied pre-heats the hydrocarbon vapors within the the plug and the combustion chamber and thus produces the necessary gasification desirable to quick starting of the engine.

While I have shown and described my invention as embodied in the forms which I at present consider best adapted to carry out its purposes, it will be understood that it is capable of modifications, and that I do not desire to be limited in the interpretation of the following claim except as may be necessitated by the state of the prior art.

What I claim is:

In a spark plug including a shell having a chamber therein closed at its top end and opening, downwardly, an insulator removably secured in said shell above said chamber extending downwardly through said chamber and an electrode extending through said insulator and projecting from the lower end thereof, a heating coil located wholly within said chamber around said insulator and having its lower end grounded to said shell, a non-heating current conducting wire connected at its one end to the top end of said heating coil and forming a continuation thereof extending upwardly through said insulator and emerging above said shell, said current conducting wire upon emergence from said insulator extending along the surface of said insulator, said insulator being reduced abruptly in diameter above said shell and continued endwise in a relatively short part parallel to the longitudinal axis of the insulator and to the upwardly extending exposed end of said current conduiting wire, that part of said insulator beyond said part parallel to the longitudinal axis oi the insulator being tapered endwise, an annular contact member encircling said insulator over and in engagement with said exposed end of said wire, said annular contact member being movable into and out of engaging position with said exposed end of said wire over the tapered part of said insulator, and current conducting means connecting said annular contact member with the source of electric energy.

LEO COUGHLIN.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,191,193 Klein et a1. July 1 1916 1,227,470 Mack May 22, 1917 1,480,477 Sule et al. v Jan. 6, 1924 1,667,960 Theis May 1, 1928 1,690,135 Seekam Nov. 6, 1926 2,631,029 Hopkins Oct. 5, 1943 

